Colo is also a good point often as you can fully manage the network from A-Z.
Note the only harder thing is when you have issues, for example I pay a bit extra because it’s quite near me so I can go on site my self. Remote hands are good but often quite expensive at the end.
64gb is not a lot, I would definitely go with 128 or even more.
By our side our public cloud (in Switzerland) uses 512gb ram nodes with 64-128 cores Amd CPU’s.
We often use large SSD to reduce the costs.
Open stack is a good choice however sometimes it’s really challenging be sure to try the things out.
We also have a cluster of a few PB for object storage across 2 DC’s, the most important for it is to save it on multiple machines.
So I would add another machine for it.
Remember if you start big at the beginning you won’t need to work out on it after it.
It’s mainly interesting in Colo as you pay your own machine, and if you have a 4gb ram machine it’s the same price as a 1tb ram machine.
Of course the best is to take the most memory per diem (for example 32gb per slot).
Like this if you need to scale you simply add more ram, Dell machines we use for example you can easily scale to 1.5TB without too much issues.
We never buy new machines always refurbished ones with warranty on it, firstly as a business aspect it’s cheaper, let’s be honest about this one.
And secondly it’s also a good thing for our planet.
I can’t recommend you more bargain hardware to buy your dedi’s.
For example we use a dedi as firewall as the r620 is like 120$ with 32 gb of ram and a 10 core CPU with SFP connectivity.
Older machine could work out for things like the VPN, object storage and such.
Then for the Cloud nodes you need to aim some solid things, one thing you can also do is to buy only one cpu on a dual socket machine and then add a CPU later on.
Remember you can scale or via adding new machines or by upgrading the already existing machines.
Backups, redundancy are the keys, always try to “plan” outages.
The ideal is using network storage nodes, but this needs insane networking speeds, like hetzner did with the ceph storage.
Remember to pay your bills, try to go in a provider free datacenter, for example in our current datacenter we can use any Swiss fiber providers, Swisscom, Sunrise, Init7, EuNetworks, Net+, nearly all the provider we want.
We are still developing the public cloud part on our side as well, and I think we will mainly use it for our own internal machines but I am sure it will be a fun project for you!